Agents and Devices A Relative Definition of Agency

http://arxiv.org/abs/1805.12387v1

Abstract

According to Dennett, the same system may be described using a physical’ (mechanical) explanatory stance, or using an intentional’ (belief- and goal-based) explanatory stance. Humans tend to find the physical stance more helpful for certain systems, such as planets orbiting a star, and the intentional stance for others, such as living animals. We define a formal counterpart of physical and intentional stances within computational theory a description of a system as either a device, or an agent, with the key difference being that devices’ are directly described in terms of an input-output mapping, while agents’ are described in terms of the function they optimise. Bayes’ rule can then be applied to calculate the subjective probability of a system being a device or an agent, based only on its behaviour. We illustrate this using the trajectories of an object in a toy grid-world domain.